1. Field of the Invention
The present invention relates to ferrite compositions preferable for manufacturing such as a multilayer inductor, and to electronic components having said compositions.
2. Description of the Related Art
Progress in enhancement of portable equipments such as smartphones is remarkable. In recent years, employment of NFC (near field communication), non-contact power supply, and so on is facilitating; and the circuits in which higher AC current flows relative to a conventional are increasing.
Further, corresponding to the densification of the electronic components, demands for the size-reduction of the devices are still great. Q-value of an inductance element generally decreases as AC current increases or the size reduces. Under such circumstances, there is a demand for a core material, providing a high Q-value even AC current increases or the size reduces, and for the inductance element thereof.
In particular, it is required to integrally fire a coil conductor and a ferrite layer in a multilayer inductor. Thus, the sintering temperature of the ferrite composition for the multilayer inductor is required to be below the melting point of the coil conductor.
Patent Article 1 discloses a magnetic material having anti-stress characteristic by an addition of SiO2 and CoO to the NiCuZn based ferrite. The magnetic material of the Patent Article 1, however, is a material sintered at 1,050° C. or more. In addition, Q value at high current amplitude is not shown.
Patent Article 2 discloses a ferrite material having a superior DC-current superimposition characteristic by using NiCuZn based ferrite composed of spinel ferrite and zinc silicate. The ferrite material disclosed in the Patent Article 2, however, does not show Q value at high current amplitude.
Patent Article 3 discloses a ferrite material with a small magnetic loss even at high current amplitude by the addition of cobalt oxide to NiCuZn based ferrite. The ferrite material disclosed in the Patent Article 3, however, often is not possible to satisfy the requirement of the recent temperature characteristics due to a large temperature change rate of the inductance.
By the techniques of the above Patent Articles 1 to 3, although certain effects can be obtained for the characteristics each technique is aiming for, the other characteristics are often sacrificed. Further, the use will be limited when it excels in only one characteristic. Therefore, more enhanced ferrite compositions are demanded.
[Patent Article 1] Japanese Unexamined Patent Publication No. H02-137301
[Patent Article 2] Japanese Patent No. 5582279
[Patent Article 3] Japanese Unexamined Patent Publication No. 2013-060332